Method of producing glue from bones



Patented Mar. 13, 1934 UNITED STATES PATENT OFFICE IVIETI iOD OF PRODUCING GLUE FROM BONES many No Drawing. Application April 6, 1931, Serial No. 528,249. In Germany February 13, 1930 2 Claims.

This invention relates to the extraction of glue from bones and has for its object to provide a new and improved process for such extraction.

Generally speaking two methods have hitherto been adopted for the production of glue from bones. One consists in exposing bones to moist pressure (steam pressure) at temperatures above 100 (3., whereby the collagen (glue yielding substance) contained in the bones is transformed in such a manner that it is soluble in hot water. This method may be indicated briefly as the pressure method.

The other method consists in first of all completely extracting the inorganic constituents, the phosphate of lime from the bones by the action of acids, whereupon the remaining bone cartilage, the so-called ossein, can be caused to change into glue without pressure by means of hot water. This method may be referred to as the maceration method.

A brief general comparison of these two known methods brings one to the following conclusions:

The pressure method is cheaper because it re quires no acids, but it yields a glue of lower quality, since the'high temperature employed reduces the quality of the glue obtained. On the other hand, the maceration method yields better glues because this injury does not take place, but it is more expensive on account of the price of the acid used. Moreover this acid usually causes a decrease in the yield of glue, because it attacks a portion of the bone cartilage.

Experiments made by the inventor have shown that it is not necessary to remove all the phosphate of lime from the bones in order to render the bone cartilage soluble in hot water, but that it is sufficient merely to remove by chemical means a certain fraction of the phosphate in order to achieve this hot water solubility.

Thus according to the invention a method of producing glue from bones consists in first removing from the bones only a larger or smaller fraction of the phosphate of lime by means of acids. A corresponding part of the glue contained in the bones may then be obtained in higher quality by merely boiling out.

According to the invention hydrochloric acid, phosphoric acid or sulphurous acid may be used in particular for extracting a fraction of the phosphate from the bones.

It is also advantageous for the treatment of the bones with acid as well as the subsequent washing to be carried out in motion.

Further, the acidic action may be accelerated by finely grinding the bones before treating them with acid. I

If un-degreased bones are used as the initial material, grease may be obtained by boiling as well as glue, but if previously de-greased bones are used as the initial material, no further removal of grease will be necessary during the process.

This method overcomes the two above mentioned defects of the complete maceration process, customary hitherto, for obviously smaller amounts of acid are required for removing only a fraction of the phosphate of lime than for removing it completely, and this smaller amount of acid naturally attacks the bone cartilage in a substantially less degree.

The new process can for example be carried out in the following manner:

1000 kg. bones are macerated for about 24 hours with 2000 litres of l /2% hydrochloric acid, whereas the complete maceration of the same quantity of bones would require 5000 litres of 7 acid. Upon the expiration of this period the salt solution formed is run off and the bones are repeatedly washed in fresh water until the remaining acid has been completely removed.

The washed bones are then treated several times with boiling water until the largest part of the glue contained in the bones has gone into solution, although only about 40% of the amount of hydrochloric acid theoretically necessary was used.

The glue still remaining in the bones can be obtained by the pressure method mentioned above. Only one or two pressures are necessary for this purpose.

I claim:

1. The method of producing glue from bones, which comprises macerating 1000 kilograms of bones for approximately twenty-four hours with approximately 2000 liters of 7 percent hydrochloric acid, removing the solution and washing the bone material to free it from acid, and boiling glue out of the treated bone material.

2. The method of producing glue from bones, which comprises macerating the bones for approximately 24 hours with a dilute acid selected from the group consisting of hydrochloric, phosphorous and sulphurous acids in quantity substantially equivalent to 2000 liters of 7 percent hydrochloric acid per thousand kilograms of bones, removing the liquid product and washing the bone material to free it from acid, and boiling glue out of the treated bone material.

DANIEL SAKOM. 

